The present invention relates to clip type fastener assemblies which include a nut section on one end of a flexible strap or an arm which is self-securing to an opening or hole formed in a support structure to receive a bolt inserted through the hole and tightened into the nut section for fastening another member to the support structure.
Such fastening devices have been frequently referred to as clip nuts, clip-on nuts, etc. Clip nut devices are generally well known and include a nut section which can be positioned behind or underneath a panel or other similar flat surface to which another panel or other member is to be joined. Such clip nut devices usually include an arm which is resiliently movably connected to the nut section and is spaced in a preset position opposite the nut section by which the clip nut device can be resiliently clamped in place.
Clip nuts are commonly used in applications where access to either side of a panel or member will be limited for subsequent assembly of a related member so that manually holding a nut behind the hole or opening formed in the panel, or member is difficult or impossible. Clip nuts are also used where it is desired to provide self-retention of the nut which is alignable with an opening or hole such as a punched or drilled hole in the subject panel or member without resorting to riveting or other involved attachment means. Numerous applications for clip nuts are in the automotive, appliance, and aerospace industries.
Clip nuts have been frequently made of metal. Such metal clip nuts, when used for applications in areas exposed to significant moisture tend to cause galvanic corrosion around the area of application of the clip nut. Thus the metal clip nuts then are often plated with cadmium to reduce, but not eliminate, the likelihood of corrosion. In some cases lightweight, titanium clip nuts may be actually required in problem areas, but are more costly than cadmium-plated steel clip nuts. The high cost of the titanium clip nuts can present a significant cost problem for example, in the manufacture of aircraft since a great number of clip nuts, may be used on a single aircraft.
Efforts have been made to overcome various shortcomings of clip nuts. For instance, the Benn, U.S. Pat. No. 5,039,264 issued Aug. 13, 1991, describes a metal clip-on nut for enabling a panel to be secured to a metallic support structure with the clip-on nut being first resiliently secured to the support structure. The clip-on nut of the Benn patent has a portion for guiding the clip-on nut into an opening formed in the support structure with the guide portion contoured to avoid scratching and hence inducing corrosion of the engaged surface of the metal support structure. The Benn patent's clip-on nut, however, is constructed from a bendable steel material which while cadmium plated may still may be subject to corrosion as noted above.
Various clip type devices have been made in whole or in part of non-metallic, elastomeric materials. Such devices are shown in U.S. Pat. No. 4,100,368 issued Jul. 11, 1978 to Thomsen, U.S. Pat. No. 4,286,642 issued Sep. 1, 1981 to Keatly, U.S. Pat. No. 4,376,605 issued Mar. 15, 1983 to Thomsen and U.S. Pat. No. 5,599,148 issued Feb. 4, 1997 to Hirose. None of the above, however, show a device which can accommodate significant variations in the thickness of the panels to which they are to be secured. Also, none of the above devices including the '264 Benn patent appear to show a clip type device with a generally hole filling feature for resisting vibrational loads. In addition none show a device in which a metal nut member is substantially encapsulated in a plastic material.
Accordingly, it is desirable to have a clip nut type device which inhibits corrosion of the nut member and the surrounding support structure. Additionally, it is desirable to have a clip nut device which can be relatively inexpensive to manufacture and can be employed by the end user at a reasonable installation cost. Furthermore, it is desirable to have a clip nut device which securely maintains its relative position alignably with the hole or opening formed in the support structure for use in the subsequent assembly of another member to the support structure. In this regard it is desirable to have a clip nut device which locks to itself thereby assuring maintenance of its relative position alignably with the opening formed in the support structure to facilitate the subsequent assembly of the other member. It is also desirable to have a clip nut device which is not dimensionally sensitive and which can be locked onto panels or support members having a significant range of thicknesses.
The present invention is directed to a clip nut device for attachment in an aperture or opening of a support structure. The clip nut device comprises a resilient main body member having an elongated, resilient strap or connector with a first bushing projecting outwardly from one end of the strap and with a second bushing projecting outwardly in an opposite direction from the other end of the strap. The first bushing which is receivable within the structure opening or hole has a first through opening or bore. The second bushing has a second through opening but is not receivable within the structure opening or hole. A threaded nut member is supported at one end of the second opening of the second bushing. Securing means operatively associated with the first and second bushings secure the first bushing to the second bushing when the first bushing is moved partially into the second opening of the second bushing. In this manner the first opening or bore is aligned with the second opening such that the threaded nut member is aligned with the support structure opening or hole.
Here the threaded nut member, preferably, is of a metallic structure to provide adequate strength when engaged with a mating metal screw or bolt; however, the nut member is held and substantially encapsulated in the second bushing at one end of the second bore at a position spaced from engagement with the surface of the support structure to which it is to be preassembled thereby avoiding galvanic type corrosion.
In one form of the present invention, the first opening or bore of the first bushing is tapered on the inside surface such that upon moving of an associated screw or bolt through the first bore of the first bushing for engagement with the nut member, the first bushing will be flared radially outwardly to grippingly engage the support structure in or about the structure hole or opening to resist loosening from vibration.
In one form of the present invention, the securing means comprise elements formed on the outer surface of the first bushing and within the second opening, which are interengageable to secure the first bushing to the second bushing for attachment to support members having a range of thickness.
Thus it is an object of the present invention to provide a unique clip nut type device having a body member constructed substantially of an elastomeric material and a nut member for pre-assembly to a support structure with the nut member held in alignment with an aperture or opening in the support structure.
It is another object of the present invention to provide such a unique clip nut which can be used with support structures having a predetermined range of thicknesses.
It is still another object of the present invention to provide such a unique clip nut which provides filling of the aligned aperture or opening in the support structure upon engagement of a mating screw or bolt with the nut member in assembling another member to the support structure.
It is a general object of the present invention to provide a unique clip type fastener.
Other objects, features, and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, in which: